Conical electric burner



@ft 9, 1934. w- NQBLE ,975,970

' coNICAL ELECTRIC BURNER Filed Oct. l0. 1931 j 26 5 li /NSULA 770A/ Patented Oct. 9, 1934 i UNITED STATES :PATENT or-FICE coNToAL ELECTRIC BURNER A Warren Noble, Detroit, Michl., assignor to Electromaster, Inc., a corporation of Michigan Application October 10, 1931, Serial No. 567,994

` s claims. (o1. 21a- 19) V vide an improved form of connector for connecting the ends of a pair cf resistor wire heating elements to a common terminal intermediate the ends of the heater circuit.

It is also an important object of my invention '1g to provide a conical electric burner having a plurality of separate spiral grooves so that a plurality of resistor wire heating elements may be placed in position in the grooves for selective and independent operation. l

Other and further important objects of my invention will be apparent from the disclosures in the following specification and accompanying drawing. Y

In the drawing: y Y

Figure 1 is a sectional View, with parts in elevation, of a conical electric burner embodying the principles of my invention. Y

Figure 2 is a side view in elevation of my iinproved connector, with parts broken.

Figure 3 is a part sectional View of a conical electric burner, with parts in elevation to show details of electrical connections.

Figure 4 is a top view of the burner.

This application is, in part, a continuation of my Patent No. 1,881,881, issued October 11, 1932, and entitled Heating element.

As shown in the drawing:`

The numeral 10 indicates a hollow conical body of refractory material. A pair of spiralled resistor wire heating elements 11 and 12 are wound on the exterior face of the cone and are each positioned in a separate and continuous spiralled groove extending from the base to the tip of the cone. l

Referring to Figure 3, the cone 10 has a slot 13 in a depending integral annular portion 14, and this slot 13 enters the starting end of a groove l5 in which the heating element 11 is placed. Directly opposite the slot 13 is another slot 16 which enters the starting end of another groove 17 in which the heating element 12 is positioned. These grooves extend to the top end of the cone, where an end of each of the heating elements passes through slots 18 and 19 and `55 enter a recess 20 in the head of the cone. The

two ends 21 and 22 are welded together at 23,

Fig. 2, andare also welded to a connector 24 of suitable material.

If the ends 2l and 22 are merely welded together, it is a very difficult matter to form the joint so that its resistance and expansibility is similar to that of the wires, and the joint is likely to form a hot spot. Welding also is likely to unduly stillen the wires about the joint, so that, with the temperature changes experienced in service, the wires are likely to crack at or close to the joint.

I have found that the connector 24, now to be more fully described, securely anchors the ends of 'the heating elements and eliminates uni due heating at the joint and the breaking of the wires at or near the joint. Y

The connector 24 may be formed of a substantially rectangular thin strip of metal which is cut to provide an intermediate dependingy apron 25 and end wing portions 26, which are bent over therwire ends 21 and 22 and pressed, tightly clamping the wires to anchor them. As shown in Figure l, the clamping wings 26 are positioned in the slots 18 and 19 and rest on the body of the cone 10. lThe apron 25 is slightly bent or curved to lie snugly against a terminal rod 27, to which it is spot-welded at 27n near the tip of the rod. t

The ends 21 and 22 of the resistor wires are curved between the clamping wings 26 and where they are welded together and to the apron at 23 to provide for expansion and contraction due to temperature changes so that there is no strain on the weld.

Integrally formed on the interior of the cone 10 are a plurality of ribs 28 which enter between spaced upstanding lugs 29 formed on a terminal block 30, of refractory material which is adapted to cooperate withl a suitable terminal socket (not shown). The ribs 28 also abut the upper surface of the block 30, whereby the cone 10 is supported on the block 30, but is not rigidly connected thereto.

' The rod 27 passes through an aperture 31 in the block 30 and is secured to the block by means of a nut 32 threaded on the rod, and an enlarged portion or integral extending arms 33 seated on the block in a suitably shaped recess 34 formed in the block. A resilient lock washer 35 is interposed between the nut 32 and the lower face of an integral depending neck portion 36 of the block 30.

It will be evident that the block 30 serves as a support for the rod 27. The length of the The starting end of the heating element 11 isA suitablyl connected to a ring 37 of wire coiled around an enlarged portion 38 of the neck 36, and the starting end of the heating element 12 is suitably connected to a wire ring 39 coiledabout the neck 36.

It Will be evident -that the burnerV may beV connected to a three-wire rsystemV with the rod 27 connected to the neutral, and that the heat-fy ing elements may also, by simplek switch, means, be connected to operate in parallel, or in series, or singly, as desired. -Y v It willy be understood that the Atwo heating elements l1 and'l2 may, in fact, `consist of a single spiralled wire element having al rnonspiralled portion thereof for connection to the rod 27. The elements would then be connected to the rod 27 by spot-welding the straight portion of the wire to the apron 25.

The connector 24 provides means for anchoring spaced apart portions of the wire so 'that Ano strain' is thrown on the weld as the heating elements expand and contract, and so that the `straight portion ofY the wire may bev `bent to form an expansible loop about the weld. The apron 25 also provides ample heatV and current conducting surface to keep the welded connection between it and the Wire relatively cool,

and, at the same time, it provides meansV for connecting the wire tothe rod 27 by another welded connection. Y

i I am aware that many changes may be made, and numerous details of'constructionY may be varied through a wide range without departing 'from the principles of this invention,VV and I,

therefore, do not purpose limiting the patent -granted hereon otherwiseV than necessitated by the priorart. Y

I claimzi 1. An electric burner `comprising a body supported for axial movement, heating elements on said body having a Vcommon section, means anchoringy the common section'of said heating elements, said means comprising a connector body having a recess, said anchoring means comprising a connector having spaced parts clampingly engaging spaced portions of said common connection, and having an intermediate portion entered in said recess.

3. An electric burner comprising an elongated body, heating elements on said bodylhaving a common connection at adjacent ends, said body having a recess at one end-thereof and having slotscommunicating with said recess formed in a ywall thereof, means anchoring the adjacent ends of said heating elements, said means comprising a connector having parts in said slots clampingly engaging spaced portions ci said common connection, and having an intermediate portion'entered in said recess.

4. `An electric burner comprising an elongated hollow body having a closed end with an aperture therein, a heating element on said body, a terminal block disposed in the other end of said body, said block 'and 'body `having a sliding engagement, a terminal Irod carried byf said block extending thru said aperture and electrically connected to said element, wherebyA said vbody may be axially moved relative to said block and T rod, and means to limit said movement.

5. An' electric burner comprising a Y.refractory hollow cone shaped body having 'an apertured closure Vinwardly disposed from'its small end, a pairof diametrically opposed slots fat saidgend, l a terminal block disposed' in the large-*end jof said body, said block and body havingasliding engagement, a terminal rod carried byfsaid block -extending thru said aperture-,' wherebypsaid cone may be axially moved relative to said blcckand rod, a wire heating velement on said cone extending thru said slots, a connector secured toA an end of said rod and having parts in's'aid slots clamp`- ingly engaging spaced portions of said wire, and means to limit the axial movement of saidbody. 51115 6. An electric burner` comprising a refractory hollow cone shaped body having an apertured closure inwardly disposed from its small -'end, a pair of diametrically opposed'slots at said? end, a terminal block disposed in the large end of i120 said body, saidblock and body having relative axial movement,f1ugs on the interiorof i said conedisposed to`abutsaid block, a terminal rod carried by said block extending'thrufsaid aperture, al wire heating element on said cone exi tending thru said slots, and a connector secured to an end of said rod having oppositely extending armsy disposed for movement longitudinallyY of said slots, said arms being clampedto spaced portions of said wire, said lugs and arms cooper- 30 ating to limit theaxial movement of said cone, whereby said cone is supported free lof'compression.

Y WARREN NOBLE-.'-

iso 

